i got mine in less than three weeks. you could hook it up as mentioned above but id rather see what voltage my amp is ACTUALLY getting. not the common voltage of the car.
you could run a wire from the amp to the front where the volt meter is. and switch it or use a relay and wire it into your head unit remote turnon so it comes on when your head unit comes on..
its a nice unit VERY clear display.. the background glows blue not super bright or harsh and the letters are highly defined black large numbers.. you could litearlly read it 10 feet away.. the biggest plus is that its no where near as bright as the stingers.
i would highly suggest them.. there is also an adjustment screw on the back just like on the stingers. so if you have a highly accurate way of measuring you can match it.